Blackfin arch: add supporting for double fault debug handling
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
diff --git a/arch/blackfin/Kconfig.debug b/arch/blackfin/Kconfig.debug
index c468624..0afa898 100644
--- a/arch/blackfin/Kconfig.debug
+++ b/arch/blackfin/Kconfig.debug
@@ -22,6 +22,44 @@
hardware error interrupts and need to know where they are coming
from.
+config DEBUG_DOUBLEFAULT
+ bool "Debug Double Faults"
+ default n
+ help
+ If an exception is caused while executing code within the exception
+ handler, the NMI handler, the reset vector, or in emulator mode,
+ a double fault occurs. On the Blackfin, this is a unrecoverable
+ event. You have two options:
+ - RESET exactly when double fault occurs. The excepting
+ instruction address is stored in RETX, where the next kernel
+ boot will print it out.
+ - Print debug message. This is much more error prone, although
+ easier to handle. It is error prone since:
+ - The excepting instruction is not committed.
+ - All writebacks from the instruction are prevented.
+ - The generated exception is not taken.
+ - The EXCAUSE field is updated with an unrecoverable event
+ The only way to check this is to see if EXCAUSE contains the
+ unrecoverable event value at every exception return. By selecting
+ this option, you are skipping over the faulting instruction, and
+ hoping things stay together enough to print out a debug message.
+
+ This does add a little kernel code, but is the only method to debug
+ double faults - if unsure say "Y"
+
+choice
+ prompt "Double Fault Failure Method"
+ default DEBUG_DOUBLEFAULT_PRINT
+ depends on DEBUG_DOUBLEFAULT
+
+config DEBUG_DOUBLEFAULT_PRINT
+ bool "Print"
+
+config DEBUG_DOUBLEFAULT_RESET
+ bool "Reset"
+
+endchoice
+
config DEBUG_ICACHE_CHECK
bool "Check Instruction cache coherency"
depends on DEBUG_KERNEL